Drive for tube reduction mills



March 14, 1967 w. VOM DORP DRIVE FOR TUBE REDUCTION MILLS r 0 W U m m Me 0 a m w s n m W 0 a e V s m m wm J M H 2 m M mm .0 m W 5 h o 3 m m E 2L. W 255 m m d m \wQ\|\ F March 14, 1967 w, voM DoRP 3,308,644

DRIVE FOR TUBE REDUCTION MILLS Filed Dec. 2, 1963 v 2 Sheets-Sheet 2 (3i! i l l I; .1 IL 11.

//7 van/0r Wa/fer 1/0/27 00/,0 By his af/omys Ilnited States Patent(Mike 3,308,644 DRIVE FOR TUBE REDUCTION MILLS Walter vom Dorp, Rheydt,Germany, assignor to Mannesmann-Meer Aktiengesellschaft,Monchen-Gladbach, Germany, a German company Filed Dec. 2, 1963, Ser. No.327,458 3 Claims. (Cl. 72-249) In the continuous production of tubing, atube is reduced by being passed through a series of roll stands, eachhaving two roll heads, one directly behind the other in the direction ofrolling. These stands are driven by a prime mover, normally a motor,through a main shaft which in turn activates geared drives, one for eachroll head. The geared drives are of conventional construction and areconnected to the roll heads, whereby power is transmitted from the mainshaft to the roll heads. The geared drives conventionally have anauxiliary adjustable element by means of which the output of the geareddrives can be varied. These adjustable elements (which may becontrollable individually or in common) are conventionallyhydraulic-mechanical in character.

Each roll stand, then, conventionally has two geared drives and twoauxiliary drives, one each for each roll head, associated with it, andthe characteristics of these drives influence not only the cost of thedrives themselves but also the economics of the entire installationthrough their bearing on roll distance, roll head construction, ease ofinspection, ease of access and space required.

Many efforts have been made hitherto to improve the economics of rollingmills. However, these efforts have the defect that the conventionaldrives used with the roll stands have not been examined as critically asthe roll stands themselves. For example, progressive ideas .advanced inregard to the economical erection of roll stands have been combined withconventional drive arrangements so that the overall installations haveoffered no possibility to the work planner for laying out a rationalspace distribution. For example, attempts have been made for some timeto keep the distance between roll stands as small as possible to limitthe scrap at the thickened ends of the stock being rolled to a minimum.In the case of a multi-stand mill this has resulted in a shortening ofthe depth of the row of roll stands in the direction of rolling.However, the associated drives have always occupied the same space andhence, the depth of the drive row remained the same.

Moreover, each roll stand and its associated drives are normallyconnected by a shaft containing a universal joint. Since the row ofstands is of a different depth than the row of drives these shaftsassume a fan-like pattern. But since the angle that can be tolerated forthe universal joint in the extreme stand-drive coupling is limited, thedistance between the drive row and the stand row cannot be decreasedbelow a certain minimum, thus setting a minimum width for the entireinstallation. This minimum is magnified because in the conventionalinstallations the various elements of each drive are arranged one afterthe other, spreading the drive out so that the entire plant requires anarea which has no relation to a rational space economy.

The present invention overcomes these shortcomings by making it possibleto erect, for a modern tube reducing mill with the smallest possibledistance between stands, an asociated drive which is not only equal indepth to the roll stands, but also is considerably shorter in width. Aunit in accordance with the invention is disposable within the smallestspace in a manner permitting economical production, thus favorablyinfluencing 3,398,644 Patented Mar. 14, 1967 the cost factor, whilststill being capable of simple operation and easy inspection.

In accordance with the invention, these and other objects are achievedby means of a drive in which the drive elements for the two roll headsof a roll stand including the totalizing or differential gear element,bevel gear means for transmitting power from the prime mover to theditferential, a superimposed drive associated with the differentialdrive, and a subsequent step-down drive are included in a singlehousing, the elements for one of the roll heads being positioned abovethose for the other in mirror symmetry about a horizontal planeseparating them. This arrangement enables the depth of the drive housing(in the direction of rolling) to be equal to two roll heads, and itfollows that the depth of the drive row is equal to the depth of theroll stand row. This obviates the need for fanning the universal jointshafts connecting the drives to their associated stands. Furthermore,the distance from stand to drive may be shortened as much as the maximumbending angle of the universal joint shafts at the load to betransmitted, permits. With a permissible bending angle of 15 this maymean a space saving of about 50% as compared to prior arrangements, sothat a shortening of the'total width of the installation may be reducedthereby.

Costwise, producing a well thought out housing results not only in asaving in material and work hours, but also in the square feet requiredin the producing area. This offers a substantial contribution toward therational over-all planning of the plant, which is expressed economicallyin the lower cost and high quality of the installation as well as betteraccessability and ease of inspection.

The invention is further described in connection with the drawings inwhich FIG. 1 is a schematic view in elevation of a conventional rollingmill installation;

FIG. 2 is a schematic view in elevation of a rolling mill installationin accordance with the invention.

FIG. 3 is a schematic plan view of the installation of FIG. 2.

Conventional roll mills have been constructed on the assumption that therequired drive units must be housed separately in order that a breakdownmay be quickly repaired. This problem makes a complete substitution foreach unit necessary, so that keeping a replacement stock is a costlymatter. Experience shows that most replacement requirements are forsmall, highly stressed parts, hardly making it worthwhile to maintain solarge a stock pile. A consequence of maintaining a collection of units,because of the necessary connections between them, is that the roomrequired for storing spare parts is very great.

FIG. 1 shows such a conventional installation. Referring to that figure,a prime mover, shown as an electric motor 1, drives a shaft 2 whichconstitutes the input of a transmission assembly 3, which, as shown,comprises a bevel gear unit 3a and a spur gear unit 312. Power istransmitted from the transmission assembly 3 to a totalizing ordifferential drive (Summengetriebe) 4 via a shaft 30 and to an auxiliarydrive 7 via a shaft 3d. The auxiliary drive 7 also feeds an input toditferential drive 4 via a shaft 7a. The output from the differentialdrive 4 is sent via a shaft 4a to a step down gear train 5 and thencevia shaft 15, which includes universal joints 15a and 15b, to a rollstand 6.

The units described above are entirely conventional and will readily berecognized by those skilled in the art.

Power transmitted from the prime mover 1 turns shaft 30 via bevel gears3a and thus turns spur gears 3b and shaft 30. Spur gears 3]) drive shaft3a which operates 'a fluid pump 9 which in turn drives an hydraulicmotor 10. The pump 9 and motor 10 are of known design and are describedin the United States patent to Thoma 2,177,613. See also Oil Power andIts Industrial Applications, Ernst, McGrawHill, New York, 1949, pp. 124,132, 133, 183. Taken together they are sometimes known as a Thomatransmission. The. speed of the motor It) is controlled via an arm 11which is pivotally mounted on a sleeve 12 which is threaded on a shaft13. A small electric motor 8 is provided for rotating shaft 13 via gears14 and thus adjusting the setting of pump 9, and hence the speed of thehydraulic motor 10.

As shown in the drawing, the motor 10 drives shaft 7a, which, with shaft30, constitutes an input to the differential or totalizing drive 4 whichis superimposed on the input delivered by shaft 30. The particular typeof differential disclosed comprises a ring gear 16 which is providedwith outer gear teeth 17 on its outer rim and also inner teeth 18 on aninner face. The outer teeth 17 are egaged by a spur gear 19 which isturned by the shaft 7a.

The shaft 3c carries a sun gear 20 which is positioned at the center ofring gear 16. A plurality of planetary gears such as 21, 22 rotatablymounted on a plate 23, are interposed between sun gear 20 and the innerteeth 18 of the ring gear 16, engaging both gears. The shaft 4a is fixedto the center of plate 23 and drives, through step down gearing 5 andshaft 15, a roll head of roll stand 6. It will be obvious that the powertransmitted from differential drive 4 through shaft 4a is a resultant ofthe power transmitted directly from the prime mover through shaft andthat transmitted through the auxiliary drive through shaft 7a. Thislatter is, of course, controllable by controlling the setting of pump 9.

As can be seen from FIG. 1, the conventional arrangement is spread outover a comparatively large space and requires a large area. Moreover,one of these assemblies is required for each of the roll heads ofeachroll stand.

FIG. 2 represents an arrangement according to the invention. As will beseen readily from a comparison of FIGS. 1 and 2, all of the individualdrive units except the auxiliary drive have been combined in a singlehousing. This single large housing, moreover, encloses not only thedrive units for a single roll head but for the two roll heads of a rollstand. Broadly speaking, this effect is obtained by locating the driveunits for the two roll heads of a roll stand, above one another inmirror symmetry about a horizontal plane. This pattern is carried out inone housing for the auxiliary drive and in a second housing for theother drive units. It is further essential that the drive housing issymmetrically divided in the vertical plane to allow for the farreaching simplilied construction.

Considering now the construction of FIG. 2 in detail:

Prime mover 31 which may be an electric motor, drives a main drive shaft32. Mounted on the main drive shaft is a beveled gear 33 which engagesand drives a second beveled gear 34 mounted on a shaft 35 Also mountedon the shaft 35 is a spur gear 36 which engages a second spur gear 37mounted on a shaft 38.

The shaft 35 is mounted to pass through a ring gear 39 and has fixed onits end, positioned inside the ring gear 39, a sun gear 40. The ringgear 39 has outer teeth 41 :and inner teeth 42. A plurality of planetarygears 43 are interposed between the sun gear and the inner teeth 42 ofring gear 39. These planetary gears 43 are each rotatably mounted on aplate 44 which is in turn fixed to a shaft 45. The shaft 45 provides theinput of a reducing gear train 46 through which a shaft 47 is driven.Shaft 47 drives (through connections not shown), one roll head 86 of aroll stand 48 through universal joints 87 and 88 and a connecting shaft89.

draulic motor 51 of the same type. Motor 51 in turn drives a shaft 52 towhich is fixed a gear 53. The gear 53 is arranged to mesh with outerteeth 41 on ring gear 39.

The input furnished through shaft 52 is varied in known manner byvarying the angle of pump 49. Thus an auxiliary servo-motor 54 isarranged to drive a threaded shaft 55 by means of gearing 56. A nut 57on shaft 55 is connected to pump 49 via an arm 58. The angle of the pump49 may thereby be varied and the rate at which motor 51 and shaft 52 aredriven, adjusted.

A comparison of that portion of FIG. 2 which has just been described,with FIG. 1, will show that the gears 33, 34, 36 and 37 correspond tothe transmission assembly 3 of FIG. 1, the gears39, 40, 42 and 53 to thedifferential drive unit 4 of FIG. 1, the gear train 46 to the gear train5 of FIG. 1 and the pump-motor combination 49, 51 to the auxiliary driveunit 7 of FIG. 1. In the device shown in FIG. 2 all the elements, exceptthe hydraulic pump and motor 49, 51 are enclosed in a common housing 59.A separate housing 60 encloses the hydraulic pump and motor 49, 51.Moreover, in accordance with the invention, the housing 59 includes asecond complete set of driving elements corresponding to thetransmission assembly, differential drive and reducing gear train andthe housing 60, a second complete auxiliary drive. In each case theseare arranged above the units already described in such a position as tobe in mirror symmetry with the lower units about a horizontal planindicated, as A-A in FIG. 2.

Thus, the gear 37 which, as described above, is driven from the primemover 31 via bevel gears 33, 34 and spur gear 36 meshes with anintermediate spur gear 61, and through this gear 61 drives a spur gear62 and shaft 63. The gear 62 in turn meshes with a gear 64 and throughit drives a shaft 65. The shaft 65 carries a sun gear 66 which mesheswith planetary gears 67 which engage the inner teeth of the ring gear68. The planetary gears 67 are rotatably mounted on a plate 69 to whichis fixed a shaft 70. The shaft 70 drives reducing gear train 71 andthrough it shaft 72. Shaft 72 through universal joints 9i) and 91, andconnecting shaft 92 drives a second roll head 93 in the roll stand 48.

The shaft 63, driven by gear 62, drives a pump 74 which is adjusted byauxiliary servo-motor 75, gearing 76, shaft 77, nut 78 and arm 79, inthe manner described above. The pump 74 drives hydraulic motor 80, whichin turn drives shaft 81 and gear 82 which meshes with outer teeth 83 ofring gear 68.

Thus, it will be seen that the device according to the invention asshown in FIG. 2 comprises two complete drive units for the two rollheads of one roll stand located one above the other, in mirror symmetryabout a central horizontal plane. The effect of this arrangement isshown more fully in relation to space requirements and ease ofinspection, in FIG. 3. 7

Referring to FIG. 3, it will be observed that the drive unit outputshafts 72 and 47 are arranged vertically above one another in the planeof the vertical seam 94 of the drive housing 59. The shafts 81, 63, 38and 52 connecting the auxiliary drive and the drive unit are alsoarranged one above the other in this vertical plane.

The thing which is immediately apparent from FIG. 3, however, is thatthe usual fanning out of the connecting shafts 39, 92 connecting thedrives with the roll stands which require bending solely in thehorizontal plane, is eliminated; if an angle of 15 is used as shown inthe drawing, a saving in the distance A of about 50% is possible.

Also the total depth of the row of drives 84 corresponds to the totaldepth of the row of roll stands '85, a fact that is made possible bythedouble drive of the invention, whose individual depth B is equal to thedepth B, of the roll stands each-containing two roll'heads.

In addition, the Width can be reduced because Within the double drivehousing 59, all mechanical drives are combined; and because the lengthof the universal joint connecting shafts such as 89 and 92, can -'beshortened due to the fact that the depths of the drives and roll standsare equal.

Equipment constructed in accordance With the invention makes it possibleto double the effectiveness of the installation which can be put in agiven space.

What is claimed is:

1. In a rolling mill installation com-prising a plurality of rollstands, each having two roll heads, and a drive assembly comprising amain drive shaft from which drive units are driven, one drive unit foreach roll head, each drive unit having a transmission element comprisingbevel and spur gear assemblies, a totalizing drive element with amechanical super-imposed drive element and a step down gear trainelement, the improvement Which comprises positioning the transmissionelement, totalizing drive element and step down gear train element forthe two roll heads of a roll stand in a single housing in mirrorsymmetry to one another With respect to a horizontal plane passingthrough the center of the housing, and driving one of said drive unitsby means of a spur gear driven by the transmission element of the otherunit.

hydraulic auxiliary drive furnishing the super-imposed drive for thetotalizing drive element, and 'being driven from the transmissionelement or" said drive unit, the auxiliary drives for the two roll headsof a roll stand being located in a single housing in mirror symmetry toone another with respect to a horizontal plane passing through thecenter of said housing.

3. Apparatus as claimed in claim 2 wherein the auxiliary drives areconnected to the drive units by shafts and shafts are provided fordriving the roll heads from the drive units, all of said shafts beingpositioned in a vertical plane passing through the center of the driveunit.

References (Iited by the Examiner UNITED STATES PATENTS 113,708 4/1871Tranter et al. 72-227 1,883,338 10/1932 Connors 72221 2,124,677 7/1938Talbot 72-221 3,136,185 6/1964 Benteller 72226 CHARLES W. LANHAM,Primary Examiner. R. J. HERBST, Assistant Examiner.

1. IN A ROLLING MILL INSTALLATION COMPRISING A PLURALITY OF ROLL STANDS,EACH HAVING TWO ROLL HEADS, AND A DRIVE ASSEMBLY COMPRISING A MAIN DRIVESHAFT FROM WHICH DRIVE UNITS ARE DRIVEN, ONE DRIVE UNIT FOR EACH ROLLHEAD, EACH DRIVE UNIT HAVING A TRANSMISSION ELEMENT COMPRISING BEVEL ANDSPUR GEAR ASSEMBLIES, A TOTALIZING DRIVE ELEMEMENT WITH A MECHANICALSUPER-IMPOSED DRIVE ELEMENT AND A STEP DOWN GEAR TRAIN ELEMENT, THEIMPROVEMENT WHICH COMPRISES POSITIONING THE TRANSMISSION ELEMENT,TOTALIZING DRIVE ELEMENT AND STEP DOWN GEAR TRAIN ELEMENT FOR THE TWOROLL HEADS OF A ROLL STAND IN A SINGLE HOUSING IN MIRROR SYMMETRY TO ONEANOTHER WITH RESPECT TO A HORIZONTAL PLANE PASSING THROUGH THE CENTER OFTHE HOUSING, AND DRIVING ONE OF SAID DRIVE UNITS BY MEANS OF A SPUR GEARDRIVEN BY THE TRANSMISSION ELEMENT OF THE OTHER UNIT.